Compilare: user.cpp: In function ‘void read()’: user.cpp:25:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("patrate.in", "r", stdin); ^ user.cpp:26:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:30:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &v[i].x, &v[i].y); ^ user.cpp: In function ‘void write()’: user.cpp:116:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("patrate.out", "w", stdout); ^ In file included from /usr/include/string.h:642:0, from /usr/include/c++/4.8/cstring:42, from /usr/include/i386-linux-gnu/c++/4.8/bits/stdc++.h:48, from user.cpp:1: In function ‘void* memcpy(void*, const void*, size_t)’, inlined from ‘int Ok(int, int)’ at user.cpp:95:32: /usr/include/i386-linux-gnu/bits/string3.h:52:71: warning: call to void* __builtin___memcpy_chk(void*, const void*, unsigned int, unsigned int) will always overflow destination buffer [enabled by default] return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); ^